Material sorter

ABSTRACT

A material sorter ( 23 ) including a material sorting assembly capable of receiving, sorting, and discharging material, a chassis including mobility means, and an attitude adjusting assembly ( 14 ) extending from the chassis to contact an environmental terrain surface ( 24 ) supporting the material sorter ( 23 ) to alter the material sorter ( 23 ) attitude with respect to the environmental terrain surface ( 24 ). There is also disclosed a method of operating a material sorter.

TECHNICAL FIELD

This invention relates to an improved material sorter.

In particular, this invention relates to a modified material sorter, preferably in the form of a screening plant configured to extend the life expectancy of the mobility means, improve the ease of relocation of the plant and improve the height of the discharge assembly drop off points.

While reference through the specification will be directed toward a material sorter for separating and sorting rocks, it should be appreciated that such a device may also used be used in other industries such as the horticultural industry, the salt mining industry and other various industries that require the sorting and separating of various sizes or grades of materials, and as such, reference to rocks and rock crush should not be seen to be limiting in any way.

BACKGROUND ART

Material sorters such as screening plants have been used in various industries in order to separate various grades of material.

In particular, screening plants are often used in the mining or rock processing industries to separate various grades of material into stockpiles for sale, or for further processing. Further processing may for example be undertaken by sending the graded crush to another sorting machine for further processing or to a further processing plant.

The majority of screening plants available to industry include towed and self propelled wheels or tracks as a means of enabling movement hereinafter referred to as ‘mobility means’. These mobility means provide mobility to the screening plants, an essential feature in many quarries or work sites as the working face of the quarry, or supply of raw material, is not fixed. As such, it is an advantage to be able to keep the processing machinery as close to the supply of material as is practicable, as minimising the distance travelled by the cartage machinery (such as excavators, wheel loaders or the like), enables a more rapid job completion with less machinery wear and an overall improvement in cost effectiveness.

Although many screening plants employ caterpillar tracks, movement between quarries or the like is generally undertaken by the loading of the screening plant onto a transporter. This is due to potential road surface damage imparted by the tracks and the minimal practicable screening plant travelling speed over long distances.

Furthermore, tracked plants are significantly more expensive than wheeled plants. The cost of moving a tracked screening plant by road is also compounded by an extra tax on weight and the need for a separate road trailer to transport the plant. Moreover, the maximum height of a tracked unit, and therefore the maximum room available for the screen box and conveyors, is less than a wheeled unit because allowance must be made for the height of the road trailer when the tracked plant is being transported on a main road.

It is an advantage with tracks however that they are less susceptible to damage by rock and rock dust getting in between the mechanical workings of the tracks and as such tracks are generally more durable.

Wheeled screening plants are generally considered to possess increased mobility between quarries or the like, as they can be towed behind a truck rather than requiring loading on a transporter.

However, a disadvantage of wheeled screening plants is the ingress of fine rocks and crush of various grades into the various mechanical components of the wheels including the brakes and brake linings (also known as running gear) causing the accelerated degeneration of the mechanical components. Conventionally, the build-up of rock and dust accumulating around the running gear during operation requires hand removal before the plant can be moved, which can be time consuming and difficult. As such, the life expectancy of various components of wheeled screening plants is lower. Accordingly, even though wheeled screening plants provide many advantages over tracked screening plants, tracked screening plants are currently preferred in the industry.

It would be an advantage therefore to be able to protect the running gear in order to maintain the mobility of the screening plant without the need for an energy-intensive and time consuming process such as boxing in the wheels at the time of use or covering them heavily by material or the like. Any protection imparted to the running gear needs to be sufficiently practical to retain the vehicle's mobility.

Screening plants generally include at least one (and often more) conveyor or discharge means, and also have a material screening assembly. The screening assembly receives the material to be graded or sorted and as the material filters through various sieves or gratings, the sorted products are then released onto various conveyor belts. Each conveyor belt then moves the material to be deposited into a pile, into an awaiting vehicle, or on to a second screening machine or the like.

Increasing the size of a pile requires a commensurate increase in the size of the conveyor belt required to deposit material on top of a pile cone. It will be appreciated that a typical conical or cone shape will be formed by dropping of material from a height above the pile, and consequently a short conveyor belt would be insufficient to create a large pile. The base of the pile would encroach on the screening plant before the pile was of a large enough size to be practical. Accordingly, longer conveyor belts are desirable. However, to have such a conveyor belt be able to be attached to a screening plant requires sufficient room to pack it when the plant is being transported.

Accordingly, there is a compromise between the length of the conveyor belt and the steepness of such. The longer the conveyor belt, the less number of conveyor belts available on the machine due to packing constraints, and therefore the less useful the machine.

The steeper the conveyor belt, the harder it is for the material to ride up it, and as such cleats need to be included on the belt in order to hold the material in place. When the cleats roll over the top of the conveyor belt they often drag the material being carried back down with the cleat and therefore the pile created may be generally lopsided or the material may be dragged back down into the machinery itself.

The compromise between length of conveyor belts and steepness of such is often reached by using shorter steep belts with cleats. Short steep belts are used to allow for packability, and the steep gradient of the belt provides a reasonable sized pile of material. Accordingly, it would be an advantage to be able to raise the height of the conveyor belt without increasing its length. This would allow for the production of a large pile of graded material without losing the packability and therefore overall mobility of the screening plant itself.

In instances where there may be up to five conveyor belts included on the sorting machine, it should be appreciated that the efficiency of packing in order for transportation becomes essential. Accordingly, the more space allowable for that packing, the more useful the overall screening plant.

Furthermore, where the material is not being dumped into a pile, but being fed into another screening plant, that plant may be able to be positioned further away, therefore maintaining manoeuvrability of other heavy machinery around such, and also maintaining certain safety levels.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising ’ is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided a material sorter, said material sorter including;

-   -   a material sorting assembly capable of receiving, sorting and         discharging material, and     -   a chassis including;         -   mobility means, and         -   an attitude adjusting assembly,             characterised in that             the attitude adjusting assembly is capable of extending from             the chassis to contact an environmental terrain surface             supporting said material sorter to alter the material sorter             attitude with respect to said environmental terrain surface             during operation of the material sorting assembly.

Preferably, said material sorting assembly includes at least one of:

-   -   at least one hopper,     -   a material screening assembly including at least one screening         box, and/or     -   at least one discharge assembly.

Preferably, in use, material from the hopper is fed to the material screening assembly for screening and transport to a discharge assembly

Preferably, said discharge assembly is capable of passing material from at least one exit of the material screening assembly to a collection point external to the material sorter.

The term ‘attitude’ in accordance with the present invention should be understood to include the position, angle, inclination, separation or orientation of the chassis and material sorting assembly with respect to the environmental terrain surface supporting the material sorter. Accordingly, when the attitude of at least one point of the material sorter is altered, it should be appreciated that, in some embodiments, the chassis of the material sorter may in fact be tilted and/or raised with respect to the environmental terrain supporting surface, hereinafter referred to as ‘the ground’.

Preferably, the attitude of the chassis of the material sorter with respect to the ground may be varied by movement around at least one pivot point or fulcrum in contact with the environmental terrain surface. In further embodiments the chassis of the material sorter may be pivoted around at least one pivot point positioned on an underside of the chassis.

It will be appreciated that the whole chassis/material sorting assembly may be raised from the ground by appropriately configured attitude adjusting assemblies (e.g. utilising four rams positioned about the chassis periphery), though this adds the disadvantage of requiring support of the entire weight of the sorter plus any material being processed. Consequently, tilting or pivoting the material sorter to achieve the aims of the invention is significantly more attractive. It may however be desirable to at least partially raise the lowermost end portion of the tilted chassis from contacting the ground during pivoting.

In order to pivot a chassis with respect to the ground around at least one pivot point, it will be appreciated that either the chassis must be raised a distance above the ground in order to provide room for the pivoting movement without interference with the ground, or alternatively one portion of the chassis may be truncated or specially configured to allow tilt without contacting the ground.

In an embodiment where the material sorter is configured to be towable, a distal portion of the chassis is configured to receive a coupling mechanism of a towing vehicle, e.g. a kingpin and fifth wheel arrangement located on the chassis and towing vehicle respectively. Accordingly, said at least one pivot point may be provided by a part of the chassis already configured to provide support for the chassis in a static un-towed configuration when decoupled from a towing vehicle. Utilising the existing chassis support element to also provide the pivot or fulcrum for pivoting the material sorter during sorting operation clearly provides an efficient configuration from an operational and manufacturing perspective. It will however be appreciated that alternative configurations are possible, utilising at least one pivot point distinct from said support element.

Thus, in one embodiment, said pivot point is provided by a support element projecting downwards from the chassis, said support element being capable of supporting the material sorter in conjunction with the mobile means in an un-tilted, substantially horizontal orientation, without support from the attitude adjustment assembly.

The support element may be configured in numerous forms including a simple elongated vertical strut or leg, or alternatively including additional strengthening elements. In each case the axis of the pivoting action occurs at the lowermost point of the support element contacting the ground.

Accordingly, in some embodiments the pivot point may be positioned substantially toward the center of the underside of the chassis of the material sorter. Alternatively, the at least one pivot point may be positioned toward the portion of the chassis configured to receive the coupling mechanism of a towing vehicle.

In further embodiments, as the attitude adjusting assembly is activated, the material sorter is successively pivoted about two or more pivot points. The material sorter may, for example initially pivot about the support element, and as the one end of the chassis contacts the ground, the material sorter may pivot about that second contact point it will be appreciated that such a configuration would necessitate sufficient structural integrity for the chassis to withstand the additional load conferred by such as arrangement, together with an sufficiently stable contact point configuration at the second pivot point to prevent tipping or rocking of the material sorter.

It should be appreciated that the term ‘chassis’, while maintaining its usual meaning to one skilled in the art, should also be understood to also include the structural body of the material sorter, and as such, should also be seen to refer to the structural support housing of the conveyors, screen boxes, hopper and other devices associated with the sorter itself and includes any embodiment in which the structural function of a chassis is effectively replaced by, or integrated with a material sorting assembly to form a rigid structural object.

While various mobility means are employed for use with material sorters, in preferred embodiments, the mobility means may include wheels.

Accordingly, mobility means such as wheels may then be able to be used in conjunction with the material sorter without adversely affecting the efficiency of the sorter itself, as has happened previously due to increased wear or damage to the running gear.

It is an advantage of the present invention that should the pivot point be positioned toward the coupling mechanism region of the underside of the sorter chassis, the mobility means associated with the chassis, positioned generally away from the coupling mechanism, may then be raised off the ground and therefore away from the accumulation of debris on the ground, such as rock, rock dust or other materials that can cause damage to mechanical parts such as brakes and brake linings in the mobility means themselves.

In a preferred embodiment, the change in attitude of the chassis of the material sorter is provided by an attitude adjusting assembly.

In some embodiments, such an adjusting assembly may include a hydraulic or pneumatic ram, or rams, a manual jack system; or other raising means known to those skilled in the art.

In preferred embodiments, the attitude adjusting assembly may be a hydraulic ram assembly.

The attitude adjusting assembly is preferably provided with laterally enlarged grounding-engaging feet that provide increased stability for the pivoted material sorter and reduced ground pressure to avoid undue avoid sinkage into the surface of the work site.

Furthermore, it would be an advantage of such an attitude adjusting assembly that it would be housed, in some embodiments, within the chassis of the sorter until deployed for use.

Sorters of various configurations are used in numerous industries where sorting or grading of material may be required. While this invention specifically discusses the sorting of rocks, it should be appreciated that the separation of other goods such as rock salt grades, fruits such as olives from leaves, or stones from sand may also be undertaken, however these are listed by way of example only and should not be seen to be limiting in any way.

Most material sorters include a hopper, typically formed from a container with downward tapering sides. Accordingly, material to be sorted may be deposited into the hopper by any convenient means, including from an excavator, or another material sorter, or any other supply source used on site.

The hopper may be positioned usually toward one end of the material sorter, and material from the hopper may be placed onto a conveyor that takes the material to a series of sieves or gratings which provide for the screening of the material into various size grades, or types.

A material screening assembly should be understood to include a combination of sieves or gratings with various conveyors, washers and screening decks and at least two screening boxes. The inclusion of two screening boxes is an advantage in that it provides for greater sortability of material grades. Furthermore, due to size constraints in a mobile material sorter, the ability to house two screening boxes in combination with at least four conveyor belts is a distinct advantage over the prior art.

The assembly making up the screening process may be of a configuration well known in the art and may include screening decks, wash bars and other apparatus usually included in screening plant machinery.

It should further be appreciated that screening boxes may be vibrating in order to encourage the material to be sorted to progress through the screens or gratings accordingly, as is well known to those skilled in the art.

Also included in the material sorter as part of the screening assembly may be sieves or gratings used to sort the material. These are well known to those skilled in the art and may vary depending on the type of material to be sorted.

In the case of rocks to be sorted, heavy-duty grating may be used. The vibrating motion of the sieve or grating may cause the rocks to rotate or oscillate, and therefore, rocks of a certain diameter may pass through the grating. The oscillating motion of the sieve or grating may also allow rocks of a certain diameter but abnormal length to pass through, thereby allowing for a more accurate sort, and decreasing the chance of blockages in the sieve or grating itself due to abnormally shaped rocks and the like.

The sorted material may then be deposited from the hopper and screening assembly onto the appropriate discharge assembly.

In preferred embodiments the discharge assembly may include a conveyor belt or belts, although the term belt should not be seen to be limiting in any way. One skilled in the art would recognise the type of conveyor system used in various industries varies and as such, while a belt system may be appropriate in some cases, other types of conveyance devices may be more appropriate in other environments.

Embodiments incorporating up to five conveyor belts associated with one material sorter have been found to operate effectively, though it will be appreciated that this is not necessarily an upper maximum number of belts. The limiting factor for the number of conveyor belts is primarily the packaging constraints of fitting all the belts into and around the chassis of the sorter in a volume acceptable for transport. Accordingly, the maximum obtainable length of each conveyor belt is otherwise restricted by this packaging issue.

Accordingly, in preferred embodiments, the material sorter may include three or more conveyor belts, but not limited to this.

Mechanisms for depositing of the screened material onto the appropriate conveyor are also well known to those skilled in the art. Once the material is deposited onto the appropriate conveyor belt, the movement of the belt then conveys the material to the point of deposition.

Conveyors are well known in various industries and as such it should be appreciated that the angle of such with respect to the chassis of the sorter may be adjusted, according to the desired drop off point. Where the drop off point is created without the need to move the material sorter itself, which may be an advantage.

It should also be appreciated that the gradient of the conveyor may be adjusted accordingly also.

It is an advantage of the present invention that the tilting of the chassis of the material sorter may raise the height of the discharge assembly, particularly the in-feed height onto the conveyor from the sorter box, which, combined with the conveyor angle, dictates the out-feed height.

In preferred embodiments, the hopper may be positioned toward the coupling mechanism of the material sorter. Accordingly, the discharge assembly may be positioned at the alternate distal end, whereby tilling the chassis of the sorter around a pivot point raises the discharge assembly whilst lowering the hopper height.

By raising the height of the discharge assembly, a larger pile of material may be achieved with the same length of conveyor belt used. Where the material is being sent to another sorter, the gradient of the conveyor may be adjusted accordingly to allow the subsequent sorter to be positioned a greater distance away, or to potentially be on a different, possibly higher level within a quarry or work site environment.

By lowering the height of the hopper, machinery bringing the material to the sorter may not be required to lift the material as high before dumping it into the hopper, thereby potentially placing less stress on the machinery, and also opening the possibility for less specialised machinery to be used. Alternatively, in the case of separation of, say, potatoes from soil, the lower height of the hopper may provide less dust spread, although this is listed by way of example only and should not be seen to be limiting in any way.

According to a further aspect of the present invention there is provided a method of operating a material sorter, said material sorter including;

-   -   a material sorting assembly capable of receiving, sorting and         discharging material,     -   a chassis including;         -   mobility means, and         -   an attitude adjusting assembly capable of extending from the             chassis to contact an environmental terrain surface             supporting said material sorter to alter the material sorter             attitude with respect to said environmental terrain surface             thereby lifting said mobility means from the terrain surface             during operation of the material sorting assembly.             characterised by the steps of     -   a) activating the attitude adjusting assembly to extend from the         chassis to contact an environmental terrain surface supporting         said material sorter;     -   b) pivoting the material sorter about at least one pivot point         located on an underside of the chassis by continued extension of         the attitude adjusting assembly to a defined point to alter the         material sorter attitude with respect to said environmental         terrain surface;     -   c) operating said material sorting assembly.

It should be appreciated that a material sorter may have its attitude adjustment undertaken at any point before or during or after the operation of the material sorter.

Accordingly, in some embodiments, should the height of the piles of sorter material reach a height level with the dropping end of the conveyor belt, the machine may be further tilted during operation in order to provide for continuous operation.

It should also be appreciated that such an attitude adjusting assembly may be retrofitted to existing material sorters in order to provide a lift in height to the discharge assembly and to preserve the mobility means associated with such.

While discussions in the specification refer to the rock industry, it should be appreciated that other industries also utilise grading and screening devices and the invention detailed here may also apply to such. Accordingly, discussions regarding rock and the sorting of such should not be seen to be limiting.

It should be appreciated that the mobility of the material sorted in combination with the ability to tilt the sorter around an axis or pivot point provides a distinct advantage over the prior art. The conveyor belts associated with the material sorter may be kept at a shorter length as the achievable height of such is increased by tilting the material sorter. The mobile means allow the overall height of the material sorter to be maximised, as it does not need to be transported on a trailer. Accordingly, the material sorter may be packed down to a compact size, enabling it to be small enough and light enough to transport, but not limiting the number of conveyor belts and associated sorting means able to be included in the material sorter. Accordingly, a greater amount of conveyors and sorters are able to be included in a material sorter of its size. Accordingly, the material sorter can be used to provide greater sorting capacity and larger sorted pile sizes coupled with ease of transport

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

FIG. 1 shows a plan view of one embodiment of the present invention;

FIG. 2 shows a side view of a material sorter in a tilted position, and

FIG. 3 shows a side view of the material sorter in a packed transportable position.

BEST MODES FOR CARRYING OUT THE INVENTION

FIG. 1 shows a plan view of a material sorter generally indicated by arrow 1, including a material sorting assembly comprising a hopper (2), the upper portion of the material screening assembly (3) and five conveyor belts (4, 5, 6, 7 and 8).

FIG. 2 shows a side view of a material sorter in a tilted position ready for operation.

The material sorter, as displayed in FIGS. 2 and 3, includes a material sorting assembly comprising a chassis (9), a hopper (2), a conveyor (3) as part of the material screening assembly, an upper screen box (10) with grating of varying size indicated by a dashed line (11), a lower screen box (12) with further grating indicated by a dashed line (13), an upper conveyor (4) for receiving one level of the sorted material from the upper screen box (10), a second and third upper conveyor (5 and 6) for receiving other levels of sorted material from the upper screen box (10), and two lower conveyors (7 and 8) for receiving the sorted and rejected material from the lower screen box (12).

Also shown in FIG. 2 is the attitude adjusting assembly (14) which includes a hydraulic ram (15), lower support strut (16), upper support strut (17), mobility means in the form of tandem axle wheels (18), a support element (19) capable of being extended when the towing vehicle (20) is removed and coupling mechanism in the form of interlock point (21) for connection to the towing truck (20). The upper strut (17) includes a ratchet configuration to provide further stability to the material sorter when in the tilted position (although lift is provided by the hydraulic ram (15)), but, which is able to be released on lowering of the interlock end (22) of the chassis (9).

FIG. 3 shows a side view of the material sorter with the material sorting assembly in a packed configuration (generally indicated by arrow 23), where the attitude adjusting assembly (14) is raised above the ground in a disengaged position with the material sorter assembly and chassis in a substantially horizontal position and connected to a towing vehicle (20) ready for transportation.

Also shown in FIG. 3 is the discharge assembly, represented by conveyors (4), (5) and (7) (conveyors 6 and 8 being obscured) in a packed position suitable for transportation.

In order to deploy the material sorter, the support element (19) is extended and abuts the environmental terrain surface (24). The towing truck (20) is then disconnected from the material sorter at the interlock point (21).

The material sorter is then stably held in a substantially horizontal position by the combination of support element (19) and tandem axle wheels (18), in preparation for deployment.

When the material sorter is deployed for use in sorting material, the support element (19) may be retracted away from its fully extended state in combination with activation of the hydraulic ram (15). The hydraulic ram (15) is then extended outward from its lower extremity, exerting a downward pressure against the environmental terrain surface (24), usually being a quarry floor, causing the interlock end (22) of the chassis (9) to initially incline downward, resulting in the further retraction of the support element (19) to a minimum packed state as the weight of the chassis (9) presses the support element (19) downward.

It should be appreciated that as the hydraulic ram (15) is first activated, the interlock end (22) of the chassis (9) will tilt downward, as described above, causing the end (25) of the material sorter distal to the interlock point (21) to tilt upward, with the pivot point being around the structural element (19). As the hydraulic ram (15) is further extended, the tandem axle wheels (18) are elevated above the terrain surface (24), causing the end of the material sorter distal to the interlock point (21) to rise higher, with the pivot point of the chassis (9) shifting from the first pivot point, being the support element (19) to a second pivot point (26) at the interlock end (22) of the chassis (9).

It should be appreciated therefore that the point of pivot of the chassis may vary, depending on the length of extension of the hydraulic ram (15) and the support element (19) and as such, it will be appreciated that the material sorter (1) may about two or more pivot points without departing from the scope of the invention.

In use, material is deposited in to the hopper (2) by an excavator or wheel loader or the like (not shown). The hopper is configured with sloping sides to enable the material to feed onto the material screening assembly conveyor (3).

The material then moves from the conveyor (3) into the upper screening box (10) where the material either passes through the various levels of grating (11), or is fed into the lower screening box (12).

The material that has passed through the grating (11) is fed onto one of the corresponding upper level conveyor belts (being 4, 5 or 6).

The material fed into the lower screening box (12) then either passes through the second grating (13) and onto the lower conveyor (7) or is fed onto the final conveyor (8).

The embodiment shown in the drawings both preserves the wheels (18) from damage and increases the height of the conveyor drop off points as the chassis (9) is rotated around the second pivot point situated at the tip (26) of the interlock end (22) of the chassis (9) by the activation of the hydraulic ram (15).

The first pivot point is indicated by the support frame (19), said support frame (19) also being used to support the material sorter in a substantially horizontal position when not connected to a towing vehicle or truck (20).

A second (optional) pivot point (26) is located toward the interlock end (22) of the chassis (9).

Accordingly, the material sorter including the material sorting assembly pivots around the support frame (19), providing a first lift to the discharge assembly, where the discharge assembly may be made up of a number of conveyor belts.

The material sorter may (if yet further height is required) be further pivoted around the second pivot point (26) located toward the interlock end (22) of the chassis (9) providing a second lift to the discharge assembly. Alternatively, the point when the interlock end (22) contact the terrain surface (24) may be used as a upper limit to the pivoting action of the chassis (9) about the support element (19). The additional contact of the interlock end (22) with the terrain surface (24) further adds to the stability of the whole material sorter (1) already being provided by the support element (19) and attitude adjustment assembly (14).

It should be appreciated that the hydraulic ram (15) may be optionally secured on the environmental terrain surface (24) by pins (not shown) that enter the terrain surface, or by having an expanded base on the structural element (19) that provides stability against any lateral movement of the material sorter (1) or support against downward pressure as the weight of the material sorter is loaded on to the structural element (19).

The tilt imparted by the hydraulic ram (15) may be increased at any time during operation of the material sorter, or maximum tilt may be obtained prior to sorting operation. The tilt of the material sorter (1) may be adjusted by adjustment of the hydraulic ram (15), with hydraulic systems well known to those skilled in the art.

It should of course be appreciated that while five conveyor belts (48) as part of the discharge assembly are shown here, this should not be seen to be limiting as any practical number of belts may be associated with the material sorter and limitation is provided only by the packability of the entire system for transport.

It should also be appreciated that the entire material sorter including the material sorting assembly (3) is tilted when the attitude adjustment assembly (14) is activated. As such, while certain conveyors and screen boxes and the like may be independently tiltable, the sorter as a whole is tilted when the hydraulics are activated.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims. 

1. A material sorter including; a material sorting assembly capable of receiving, sorting and discharging material, and a chassis including; mobility means, and an attitude adjusting assembly, characterised in that the attitude adjusting assembly is capable of extending from the chassis to contact an environmental terrain surface supporting said material sorter to alter the material sorter attitude with respect to said environmental terrain surface thereby lifting said mobility means from the terrain surface during operation of the material sorting assembly.
 2. A material sorter as claimed in claim 1, wherein said material sorting assembly includes at least one of: at least one hopper, a material screening assembly including at least one screening box, and/or at least one discharge assembly.
 3. A material sorter as claimed in claim 2, wherein in use, material from the hopper is fed to the material screening assembly for screening and transport to a discharge assembly.
 4. A material sorter as claimed in claim 3, wherein said discharge assembly is capable of passing material from at least one exit of the material screening assembly to a collection point external to the material sorter.
 5. A material sorter as claimed in claim 1, wherein the attitude of the chassis of the material sorter with respect to the environmental terrain surface may be varied by movement around at least one pivot point in contact with the environmental terrain surface.
 6. A material sorter as claimed in claim 5, wherein the chassis of the material sorter may be pivoted around at least one pivot point positioned on an underside of the chassis.
 7. A material sorter as claimed in claim 5, wherein a distal portion of the chassis is configured to receive a coupling mechanism of a towing vehicle.
 8. A material sorter as claimed in claim 5, wherein said pivot point is provided by a support element projecting downwards from the chassis.
 9. A material sorter as claimed in claim 8, wherein said support element is capable of supporting the material sorter in conjunction with the mobile means in an un-tilted, substantially horizontal orientation, without support from the attitude adjustment assembly.
 10. A material sorter as claimed in claim 5 wherein the longitudinal location of pivot point is positioned substantially centrally on an underside of the chassis.
 11. A material sorter as claimed in claim 7, wherein the longitudinal location of the pivot point is positioned toward the distal portion of the chassis configured to receive the coupling mechanism of a towing vehicle.
 12. A material sorter as claimed in claim 1, wherein, said mobility means are wheels.
 13. A material sorter as claimed in claim 1, wherein, said attitude adjusting assembly includes hydraulic or pneumatic rams or a manual jack system.
 14. A material sorter as claimed in claim 1, wherein the attitude adjusting assembly is provided with laterally enlarged grounding-engaging feet.
 15. A material sorter as claimed in claim 1, wherein, said attitude adjusting assembly is housed within the chassis until deployed for use.
 16. A material sorter as claimed in claim 2, wherein the hopper is positioned toward one distal end of the material sorting assembly.
 17. A material sorter as claimed in claim 2, wherein material placed in the hopper is transferable onto a conveyor and conveyed to a material screening assembly including a series of sieves or gratings to provide size screening of the material.
 18. A material sorter as claimed in claim 2, wherein the material screening assembly includes screening boxes, decks and wash bars.
 19. A material sorter as claimed in claim 18, wherein said screening boxes are capable of vibrating during screening.
 20. A material sorter as claimed in claim 2, wherein the gradient of at least one discharge assembly is adjustable.
 21. A material sorter as claimed in claim 20, wherein the discharge assembly may be positioned at an opposing distal end to the coupling mechanism.
 22. A material sorter as claimed in claim 7, wherein the hopper is located at a distal end toward the coupling mechanism.
 23. A material sorter as claimed in claim 1, wherein said attitude adjustor is retrofitted to the material sorter underside.
 24. An attitude adjustor for retrofitting to a material sorter including a material sorting assembly capable of receiving, sorting and discharging material, and a chassis including a mobility means, said attitude adjustor including an attitude adjusting assembly adapted to be attached to the material sorter underside, wherein the attitude adjusting assembly is capable of extending from the material sorter chassis to contact an environmental terrain surface supporting said material sorter to alter the material sorter attitude with respect to said environmental terrain surface, thereby lifting said mobility means from the terrain surface during operation of the material sorting assembly.
 25. A method of operating a material sorter as claimed in claim 1, characterised by: activating the attitude adjusting assembly to extend from the chassis to contact an environmental terrain surface supporting said material sorter; pivoting the material sorter about at least one pivot point located on an underside of the chassis by continued extension of the attitude adjusting assembly to a defined point to alter the material sorter attitude with respect to said environmental terrain surface, thereby lifting said mobility means from the terrain surface; and operating said material sorting assembly.
 26. A method of retrofitting an attitude adjustor as claimed in claim 25, to a material sorter, said attitude adjustor including an attitude adjusting assembly adapted to be attached to the material sorter underside characterised by the step of attaching the attitude adjusting assembly to the material sorter underside. 27-30. (canceled) 